BronyMedic:We're running out of resources on Earth at an alarming rate.

No we aren't. We haven't destroyed any resources.* We've changed the state of a lot of our resources, of course, and that makes them a lot more difficult to use, but they're still there. All the aluminum is still out there, all the tin, all the copper, all the iron, etc. We've burned (literally and figuratively) through our planetary savings account of hydrocarbons, but they aren't gone, either. Our ecosystem will continue to make hydrocarbons from the water, carbon, and sunlight to the extent that we allow it to. There are several ways we can help that. Our fresh water may be spoiled, but it's a simple distillation away from pure again. Our soil may be polluted, but it's a not-so-simple unobtanium-powered cleansing away from being clean, too.

We really only have an alarming scarcity of two things: energy and space. Space isn't a huge concern. We haven't filled the space we have currently efficiently, technology could easily make ocean habitats to make more space, and agricultural technology could (if wrested away from the hands of Monsanto, ConAgra, and the like) significantly reduce the amount of space required to feed us. I don't personally believe we'll ever fill the planet, as we're somewhat self-regulating as a species. We'll swing too far for a few centuries, and come to rest at a sustainable level--as long as we can keep from destroying civilization with war.

So, that leaves us with one huge problem: energy. Free or nearly-free energy would solve all our problems. With enough energy, we can desalinate all the water we like. We can filter landfills through huge factories to recover waste raw materials. We can produce fertilizers from hydrocarbons if we choose. Hell, if we really get cramped, we can launch orbital farm satellites. Whatever the hell we want, we can do with enough energy. That's what we can do as a species to ensure our survival. Personally, I like the genetically engineered algae that crap jet fuel as a solution, but there are all kinds of possibilities. Let's get the hell to work.

*I suppose you could consider that we've destroyed radioactive resources, but they are self-destroying, anyway. Nothing a particle accelerator wouldn't fix.

**Don't get me wrong. I am a firm believer that we should be colonizing the galaxy, just not for that reason. It is impossible for us to leave the earth. New births would outnumber any amount of colonists we could launch effectively forever.

TopoGigo:So, that leaves us with one huge problem: energy. Free or nearly-free energy would solve all our problems. With enough energy, we can desalinate all the water we like. We can filter landfills through huge factories to recover waste raw materials. We can produce fertilizers from hydrocarbons if we choose. Hell, if we really get cramped, we can launch orbital farm satellites. Whatever the hell we want, we can do with enough energy. That's what we can do as a species to ensure our survival. Personally, I like the genetically engineered algae that crap jet fuel as a solution, but there are all kinds of possibilities. Let's get the hell to work.

I like very much where you're going with that. I've been down the same course. If you wanna go beyond the level of internet advocacy, join NSS, go to ISDC and other space conferences & meet some awesome people.

I'm pretty well convinced that lunar ISRU solar (and likely asteroid ISRU pretty shortly thereafter) will be the thing that really blows open the space economy, allows people to start living in space or have basically unlimited options as far as access to fresh water and food on the Earth's surface. There is SOOO much space, and so much energy - the earth is a tiny pinprick of shadow on the giant beachball of the Sun's radiated energy, intercepting only two-billionths of the 370 trillion terawatts the sun emits, mostly into cold, uncaring deep space. The potential for space-based solar power capture is practically limitless in comparison to what we humans use - around 6TW of electricity, vehicle fuel, and industrial process energy if I recall correctly. Also, the matter available in the asteroid belt alone has been estimated to be plenty to support 10 trillion people at US middle class standards of living; Jupiter and its moons at least as much.

Yes, the technical problems can all be overcome with more energy. The underlying issues though are more complex - organization and capital. (and I'm all-too-conveniently leaving aside the systems of oppression, of wars, of classism... capitalist-imperialist, religiously-motivated and otherwise) Thing is, at least in the US and Europe, ppl are still plenty rich in terms of spending $$$$ on inane unnecessary stuff. These societies have plenty of water and food and will for a long time despite what doomsayers doomsay. Yes, we do have rivers, reservoirs, and aquifers drying up, but in some places the issue is that people aren't ready to pay more for water infrastructure: treatment plants, rain capture, pumps, pipelines and ultimately desalination in many but certainly not all cases; the actual amount of drinkable water is nowhere close to running out, cf. Mississipi river watershed, but in many cases it is not available where people want to continue to live, or more likely than not, it is being wasted for idiotic landscaping or corrupt/outdated agricultural subsidies (fark forgot how much this stuff pisses me off). If it was just energy people would be okay, but there'd also need to be substantial physical changes to the landscape to move water - installing aqueducts is more complicated than just adding a couple cents per cubic foot of water to customers' electric bills!

A typical counterpoint I hear to space-based solar is that there's plenty of incident light reaching our deserts and oceans, and in theory these would be much easier/cheaper places to direct solar energy to useful purposes. Three problems: 1. Solar is too expensive. The photovoltaic market is changing this but has hit snags (see #3) but anyway PV still has ways to go to be competitive with cheaper-but-more-maintenance-intensive solar thermal. Also space solar has a huge advantage in terms of grid realities: it provides a stable base load, vs ground solar which goes out at night and cloudy weather so must generally be balanced by equal capacity of gas turbine or other fast-switching power plants; 2. Biofuel uses too much water (ocean-based may obviate this? but containment is a hassle and saltwater biofuel tech (e.g. algae) is, stupidly, less developed than freshwater; and 3. Fracking is too cheap: the energy market has hit this big dumb distraction - the across-the-board technology improvements in fracking and horizontal drilling techniques not to mention a steady and increasing stream of capital investments such as more well pipe, pumping trucks and drilling rigs, much of it owner-operated stuff financed by got-rich-quick field hands. Anyone with half a shred of decency, of care for this planet or for future generations realizes that fossil fuels are not a reasonable way forward, and by doing what's marginally cheaper in the very short term rather than investing in better technology, we're pushing the huge windfalls of cheap biofuel, efficient ground solar and sprawling terawatt space solar arrays farther and farther futureward. But such is the logic of the market.

Of course nuclear energy is the obvious foil to to space-based solar but then again I suspect space-beamed microwaves will be a way easier sell than ionizing radiation will ever again after the insanity that gripped the world post-Fukushima. Ridiculously convenient for the oil-and-gas industry that this perfect nuclear market collapse fell into their laps: Oregon LNG terminal plans reverse from importing to exporting gas; Issues Facing U.S. Shale Gas Exports To Japan. I haven't found any exposés yet but surely at least a few mill of frackers' lobbying dollars went to defaming nuclear, not that it needed much help; hell, they gave Sierra Club $26M to shut down coal power.

Another issue is that energy projects take land, which can be controversial, see for example the HeraklesDebacle (pdf warning). Perhaps space seems more politically accessible? Not clear that's the case given that we haven't figured out space property rights, and likely won't before people just go up and start staking claims to see what happens. But again, space is soooo much bigger than the mere surface of the Earth that of course the long-term future of a continuously expanding population will necessarily go out there. If humanity shrinks maybe we could survive on Earth, but that would be stupid.

Right now, the cheapest ways to make investments in energy with a short-term payoff are fossil fuels and what are effectively slave-operated palm oil plantations (granted, much smaller scale in terms of energy, though not necessarily human impact). Yes, there are various other biofuels programs getting attention, and like photovoltaic and wind power they do move along where government funds get kicked in, but in general the privately funded stuff that happens without much government intervention (I've learned too much about ag subsidies and other forms of corporate welfare to believe in free markets) is fossil fuel extraction and replacement of rainforests with palm oil plantations.

The difference is a matter of financing - nobody's interested in ponying up the liquidity (currency is, after all, pretty universally how we motivate skilled workers to do things in this world) - nobody's ready to risk the capital to launch gigantic space power satellites until the technology is proven. And despite the rather solid understanding of the underlying technicalities of massive photovoltaic arrays and microwave power beaming there's really very little money going toward efforts that substantially bump up the TRL of these technologies. Despite being a solar sail mission rather than a powerplant, Japan's IKAROS was a big step to demonstrate use of thin film photovoltaics in spacecraft. Once a few more missions prove out power beaming and array maneuvers and such then people with purse strings might start taking things more seriously.

There are lots of people throughout national space agencies and astronautics departments with proposed architectures and even a few launcher-ready prototypes drawn up, but again, most people with massive quantities of money aren't looking to lock it up for years at a time when the payoff is anything but certain, and it's entirely possible that despite, say, an energy company investing $10B in a 1-megawatt space solar power pilot plant, that some alternate pathway will win out and they'll wind up not making anything back on the investment. (This $10B/1MW pilot has been presented at recent conferences. Personally, I think it could be done for a whole lot less and at a direct profit, rather than as mere R&D, but then again I have a history with projects that never make it off the ground...)

BronyMedic:Humanity's only way for long term (>150-200 years) survival is to look upwards and outwards

No it isn't. That's a pseudo-religious view popularized by sci-fi and cheesy movies. A deadly vacuum with nothing in it is no place for "survival". Modifying our lifestyle and social model right here is our only long-term hope. We should choose to do these things because they are hard, not because they are easy.

BronyMedic:We're running out of resources on Earth at an alarming rate.

Are we tossing them into a black hole?

Anyways, you loons will all still be right here in a decade, and so will everyone else. Get used to it. No amount of weeping over cheesy sci-fi artwork will change that, or hand-wringing over the "species". You people don't care about the "species", you care about your religious sci-fi stories.

ThaGravy:Jubeebee:Exoplanets are irrelevant for future human habitation anyway. If you can get humans to an exoplanet, you can sustain human life in a spacecraft for a very, very long time, essentially indefinitely.

...With essentially unlimited energy, you could make yourself a rather comfortable life close to home, rather than spending a few millennia floating through the interstellar dark.

I thought I would try to put some actual numbers to it...

The distance to the closest star is 39,900,000,000,000 km away. (link)

The fastest man-made object moves at 252,800km/hr (link)

At that distance/speed, it would take 157.8 million hours (or about 18,000 years) to get there. The ancient pyramids were build roughly 4,500 years ago.

You're not limited to the speed of a spaceprobe launched in the 1970s using a couple of chemical rocket burns and gravity assists.

Totally ignoring the effects of relativity (which means a speed limit of 0.25c for the journey), you could get to the nearest star in 678 years, with a midpoint turnaround and a constant acceleration of just 0.007g. Obviously that's way more than a human lifetime, but it's totally within the realm of possibility for a multi-generational ship (particularly if some means of long-term hibernation for the crew is discovered).

That's with something like magnetic plasma propulsion, which generates extremely low thrust. When you start delving into really advanced propulsion systems, like, say Project Daedalus, You can get the journey down to within a human lifespan, maybe 50 years to a nearby star.

And then there's crazy-exotic stuff like the Quantum Vacuum Plasma Thruster: some guy at NASA is claiming a perpetual 0.02g for a 10-ton spacecraft with a 2MW powerplant. Scale things by a factor of 1000 and you could have a 1000-ton vehicle at 0.2g on 2GW, which is within the range of nuclear power plants today. At 0.2g you'd hit 93% of the speed of light at the midway point of the journey, which would shorten the crew's perception of the travel time by about a third due to relativity. To an outside observer, the journey would take 10 years, but for the crew only about 6.

Jubeebee:If humanity is going to have any future in space, it's going to be around our own familiar star.

No, I don't think so. Humanity has never been content remaining in one place when it has the means and ability to explore. We were not content with staying around our own familiar cave; we were not content with staying around our own familiar village; we were not content with staying around our own familiar country; we were not content with staying around our own familiar continent. We will not be content staying around our own familiar star.

BronyMedic:Humanity's only way for long term (>150-200 years) survival is to look upwards and outwards.

The logistics and resources needed to move humanity across solar systems is so mind-boggling the best hope for humanity is fixing/not-ruining the planet we got. The worst case scenerio for Earth (ie nuclear fallout), is still probably most suitable for humans than the surface of whatever planet you're looking for.

SlothB77:It has found nearly 80 confirmed exoplanets with a similar size to Earth but only a few of those have the right distance from their star to support liquid surface water - the presence of which is considered essential to sustain life.

ok, why does it have to be a similar size to earth? I understand it can't be too small to fit everyone if we all decide to up and move to it, but if a planet is twice the size of earth, is it incapable of supporting life then? I mean, besides those 48 hour-long days, what is the problem? will the gravity be too strong or something?

Exoplanets are irrelevant for future human habitation anyway. If you can get humans to an exoplanet, you can sustain human life in a spacecraft for a very, very long time, essentially indefinitely.

And if you can do that, it's a whole lot easier to trade some of your fuel weight for a few acres of solar panels and park yourself in solar orbit somewhere between Earth and Venus. With essentially unlimited energy, you could make yourself a rather comfortable life close to home, rather than spending a few millennia floating through the interstellar dark.